1. Field of the Invention
The present invention relates to a tapered slot antenna and, more particularly, to a tapered slot antenna with an extended dielectric substrate as a dielectric loading for tuning the E and H field beam width.
2. Description of the Prior Art
Tapered slot antennas are generally known in the art and used in various microwave communications systems. Examples of such tapered slot antennas are disclosed in U.S. Pat. Nos. 5,036,335; 5,081,466 and 5,187,489. Such tapered slot antennas are also discussed in Antenna Engineering Handbook, 3rd Edition, McGraw-Hill, Inc., pgs. 8.4-8.9 (1993).
Such tapered slot antennas are normally formed on a dielectric substrate by photolithography techniques. Such tapered slot antennas include a metallization layer formed on one side of the substrate. A portion of the metallization layer is etched away to the substrate to form a tapered slot that extends to the edge of the substrate. A microstrip feed line is formed on an opposite side of the substrate by way of a metallized strip. The metallized strip it positioned adjacent a narrow portion of the slot, formed on the opposite side of the substrate. A plated through hole or small diameter wire is known to be used to couple the microstrip feed to the tapered slot antenna formed on the opposing side of the dielectric. When used in receiver applications, incoming electric magnetic radiation is received by the tapered slot antenna and coupled to the microstrip feed line, which, in turn, is normally coupled to signal conditioning circuitry, such as a low noise amplifier.
Unfortunately, such tapered slot antennas have asymmetric radiation patterns. In other words, the H-plane beam width is relatively wider than the E-plane beam width. As such, the gain and the coupling efficiency of such tapered slot antennas is relatively low.